I recently designed this simple voltage regulator circuit using a TL072 on LTspice (and multisim)
And the circuit worked as expected: it output 5V.
But when I built it on the breadboard, something weird and counterintuitive happened. The output of the regulator was actually 0V! When I checked the output of the op amp, it was around 14V. Now here's the funny thing. The inverting input was at 2.495V, as expected, but the non inverting input was at 0V. Despite this, the output of the op amp was 14V!
Next, I replaced the TL072 with an LM358. And guess what happened? It worked!!
Now what I want to know is why this circuit worked with the LM358 (but not the TL072) on the breadboard when LTspice and Multisim simulations clearly showed that the circuit works with the TL072.
Please let me know.
PS to get the circuit working with the TL072, I actually had to temporarily short the inverting and non-inverting inputs to get the circuit going. But that is not a proper solution. Also, the LM358 is inferior in performance to the TL072, which is why I want to find a solution and make the circuit work with the TL072.